Silk fibroins are produced by numerous species of spiders and by worms from various insects such as bees, butterflies, and moths. Silks produced by silkworms (typically Bombyx mori) and orb-weaving spiders have desirable mechanical properties, environmental stability, biocompatibility, and tunable degradation. In addition, these silks can be modified to deliver agents such as antibiotics, drugs, and growth factors to enhance healing in biomedical applications. Silk has been previously discussed in the context of biomedical applications, such as silk sutures (Vepari and Kaplan 2007).